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METHYL ESTER PRODUCTION USING FEEDSTOCK AND CATALYSTS
FROM WASTE SOURCES
IRMA NURFITRI
Thesis submitted in fulfilment of the requirements
for the award of the degree of
Master of Science (Industrial Chemistry)
Faculty of Industrial Sciences & Technology
UNIVERSITI MALAYSIA PAHANG
JANUARY 2015
vi
ABSTRACT
In the present work, waste sources, namely boiler ash, baby clam (Paphia undulata)
shell and capiz (Placuna placenta) shell have been successfully utilized as solid
catalysts in the transesterification of palm olein (RBD-PO) and waste palm cooking oil
(WPCO) to produce methyl esters (biodiesel). In order to enhance the catalytic activity,
the boiler ash had been calcined at 500 ˚C for 5 h (was labelled as BA-500), while waste
shells of baby clam and capiz have been calcined at 900 ˚C for 2 h (labelled as BC-
CaO-900 and C-CaO-900, respectively). The optimal reaction conditions found to be:
for transesterification of RBD-PO and WPCO using BA-500 as a catalyst were 3 wt.%
catalyst amount (based on oil weight) and 9:1 methanol to oil molar ratio for 1 h
reaction period, while BC-CaO-900 and C-CaO-900 with 5 wt.% catalyst amount, 12:1
methanol to oil molar ratio for 3 h reaction period. All catalysts achieved over 96.5%
methyl ester content at the reflux temperature of methanol (65 ˚C). Furthermore, the
mixed-shell catalyst of BC-CaO and C-CaO (labelled as BC-C-Mixed-900) at a 1:1
weight ratio showed similar activity as the individual catalysts. The regenerated of the
catalytic activity was investigated, and found that the BA-500 could be reused up to two
times, while BC-C-Mixed-900 catalyst reused up to seven times when maintaining
methyl esters content above 90%. In addition, the BA and BC-C-Mixed-900 catalysts
exhibit tolerance towards the presence of water at 1.75% and 2.0% and free fatty acid at
1.75% and 1.75%, respectively, with over 80% of methyl esters content. Oil extracted
from decanter cake (DC) was also investigated in this study, via in situ
transesterification with ultrasonic irradiation and mechanical stirring method. The
catalyst amount of 20 wt.% (based on oil weight), 150:1 methanol to oil molar ratio, co-
solvent:DC (1:1) weight were found as the optimal conditions, yielding 86% and 45%
methyl ester content in an hour reaction period for ultrasound irradiation and
mechanical stirring, respectively. The emissions performance of WPCO B10 blend
using BA-500 as a catalyst was investigated on horizontal single cylinder 4-stroke
diesel engine (YANMAR NF19-SK). The results indicated that the WPCO B10 blend
biodiesel gives lower CO2 and CO emission compared to commercial diesel, thus
contributed to the reduction of greenhouse gases.
vii
ABSTRAK
Dalam kajian ini, bahan buangan abu tandan kosong, cengkerang batik dan cengkerang
kapis telah digunakan sebagai mangkin pejal dalam proses transesterifikasi
menggunakan minyak sawit tulen (RBD-PO) dan minyak masak sawit terpakai
(WPCO) untuk menghasilkan metil ester. Dalam usaha untuk meningkatkan aktiviti
mangkin, abu tandan kosong telah dikalsin pada suhu 500 ˚C selama 5 jam (dilabel
sebagai BA-500), manakala cengkerang batik dan cengkerang kapis telah dikalsin pada
suhu 900 ˚C selama 2 jam (masing-masing dilabel sebagai BC-CaO-900 dan C-CaO-
900). Keadaan optimum tindak balas untuk transesterifikasi RBD-PO dan WPCO
dengan menggunakan BA-500 sebagai mangkin adalah 3% (berdasarkan berat minyak)
dan 9:1 nisbah molar metanol kepada minyak, selama 1 jam, manakala transesterifikasi
dengan menggunakan mangkin daripada cengkerang menggunakan 5% (berdasarkan
berat minyak), 12:1 selama 3 jam. Kesemua mangkin mencatat lebih 96.5 % metil ester
pada suhu refluks metanol (65 ˚C). Campuran cengkerang (dilabel sebagai BC-C-
mixed-900) pada nisbah berat 1:1 menunjukkan aktiviti yang sama seperti cengkerang
individu. Keberkesanan penggunaan semula mangkin dikaji dan didapati bahawa BA-
500 boleh digunapakai semula sebanyak 2 kali dan BC-C-mixed-900 sebanyak 7 kali
dengan kandungan metil ester lebih dari 90%. Tambahan pula, BA-500 dan BC-C-
mixed-900 masing-masing menunjukkan toleransi terhadap air pada 1.75% dan 2.0 %
dan asid lemak bebas pada 1.75%. Pengekstrakan minyak daripada decanter cake (DC)
juga dikaji melalui kaedah transesterifikasi in situ dengan kaedah sinaran ultrasonik
serta kaedah adunan mekanikal dengan 20% mangkin (berdasarkan berat minyak),
150:1 nisbah molar metanol kepada minyak dan pelarut:DC (pada nisbah berat 1:1)
telah didapati sebagai keadaan pelarut optimum, 86% dan 45% kandungan metil ester
dalam satu jam untuk kaedah sinaran ultrasonik dan kaedah adunan mekanikal. Prestasi
gas ekzos biodiesel B10 juga dikaji, hasil dari metil ester WPCO dan BA-500
menggunakan enjin diesel silinder tunggal melintang 4-lejang (YANMAR NF19-SK).
Data menunjukkan bahawa B10 menghasilkan CO2 dan CO yang lebih rendah
berbanding dengan diesel komersial, sekaligus menyumbang kepada pengurangan gas
rumah hijau.
viii
TABLE OF CONTENTS
Page
SUPERVISOR’S DECLARATION ii
STUDENT’S DECLARATION iii
ACKNOWLEDGEMENTS v
ABSTRACT vi
ABSTRAK vii
TABLE OF CONTENTS viii
LIST OF TABLES xii
LIST OF FIGURES xiv
LIST OF ABBREVIATIONS xviiii
CHAPTER 1 INTRODUCTION
1.1 Introduction 1
1.2 Problem Statement 6
1.3 Objectives 7
1.4 Scope of Study 7
CHAPTER 2 LITERATURE REVIEW
2.1 Biodiesel 8
2.2 Historical Background on Biodiesel Production 10
2.3 Global Biodiesel Production 11
2.3.1 Biodiesel in Europe 12
2.3.2 Biodiesel in United States 14
2.4 Biodiesel in Malaysia 15
2.5 Process of Synthesizing Biodiesel 16
2.5.1 Transesterification Process 17
2.6 Waste Sources of Feedstock to Biodiesel Production 20
2.6.1 Animal Fats and Grease 21
2.6.2 Spent Bleaching Clay 24
ix
2.6.3 Decanter Cake 25
2.6.4 Waste Cooking Oil 26
2.7 Extraction Techniques 27
2.7.1 Mechanical Stirring Soxhlet Extraction Method 27
2.7.2 Ultrasonic Extraction Method 28
2.8 Catalysts in Transesterification 29
2.8.1 Homogeneous Catalyst 29
2.8.2 Heterogeneous Catalyst 31
2.9 Catalysts from Different Waste Sources in Transesterification Reaction 33
2.9.1 Shells 36
2.9.2 Ashes 38
2.9.3 Rocks 39
2.9.4 Bones 40
2.10 The effect of free fatty acid and moisture in transesterification 41
CHAPTER 3 MATERIALS AND METHODS
3.1 Materials 43
3.2 Preparation of Feedstock 43
3.3 Characterization of Feedstock 44
3.3.1 Determination of Acid Value (PORIM Test Methods (p1), 1995) 44
3.3.2 Determination of Free Fatty Acid (PORIM Test Methods (p1), 1995) 45
3.3.3 Determination of Water Content 46
3.3.4 Determination of Viscosity 46
3.3.5 Determination of Density 46
3.3.6 Deterioration of Bleachability Index Analysis 46
3.4 Catalysts Preparation for Transesterification 47
3.4.1 Boiler Ash as a Catalyst in Transesterification 47
3.4.2 Baby Clam Shell as a Catalyst in Transesterification 48
3.4.3 Capiz Shell as a Catalyst in Transesterification 49
3.5 Catalysts Characterization 49
3.5.1 Thermal Gravimetric Analysis of the Catalysts 49
3.5.2 X-ray Diffraction Analysis of the Catalysts 49
3.5.3 Surface Analysis (BET method) of the Catalysts 49
3.5.4 Fourier Transform Infrared Analysis of the Catalysts 50
x
3.5.5 Scanning Electron Microscopy Analysis of the Catalysts 50
3.5.6 X-ray Fluorescence Analysis of the Catalysts 50
3.5.7 Basicity Analysis of the Waste Catalysts using Hammett Indicators 50
3.6 Transesterification Reaction 51
3.7 Analysis of methyl ester 52
3.7.1 Qualitative Analysis of Methyl Ester 52
3.7.2 Quantitative Analysis of Methyl Ester 53
3.8 Catalyst Activity 54
3.9 Transesterification using Mixed-shell-CaO Catalyst 54
3.10 Reusability, Regeneration and Leaching Study of Waste Catalysts in WPCO 55
3.11 Tolerance of Waste Catalysts Towards of Water and FFA in WPCO 55
3.12 In situ Transesterification of DC Using Ultrasound Irradiation and Mechanical
Stirring Methods 56
3.13 Determination of Fuel Properties of the Methyl Ester Products 56
3.13.1 Determination of Flash Point 57
3.13.2 Determination of Higher Heating Value 57
3.13.3 Determination of Cold Point 57
3.13.4 Determination of Sulphur Content 58
3.14 Emission Analysis 58
CHAPTER 4 RESULTS AND DISCUSSION
4.1 Characterization of Feedstock 59
4.1.1 Characteristics of RBD-PO, WPCO and O-DC 59
4.1.2 Characteristics of DC and Extraction of O-DC 62
4.2 Catalyst Characterizations 65
4.2.1 Thermal Gravimetric Analysis of the Catalysts 65
4.2.2 X-ray Diffraction Analysis of the Catalysts 67
4.2.3 Surface Analysis (BET Method) of the Catalysts 72
4.2.4 Fourier Transform Infrared Analysis of the Catalysts 74
4.2.5 Scanning Electron Microscopy Analysis of the Catalysts 76
4.2.6 X-ray Fluorescence Analysis of the Catalysts 78
4.2.7 Basicity Analysis of the Catalysts using Hammett Indicators 79
4.3 Transesterification of RBD-PO and WPCO 80
4.3.1 Influence of Calcination Temperature in Transesterification 80
xi
4.3.2 Influence of Catalyst Amount in Transesterification 81
4.3.3 Influence of Methanol to Oil Molar Ratio in Transesterication 83
4.3.4 Influence of Reaction Time in Transesterification 85
4.4 Catalyst activity 86
4.5 Transesterification using CaO mixed-waste catalyst 87
4.6 Reusability, Regeneration and Leaching of Catalysts from Waste Sources 88
4.6.1 BA-500 89
4.6.2 BC-C-Mixed-900 91
4.7 Tolerance of Waste Catalysts Towards FFA in WPCO 93
4.8 Tolerance of Catalysts from Waste Sources Towards Moisture Content in
WPCO 97
4.9 In situ Transesterification of O-DC Using Ultrasound Irradiation and Mechanical
Stirring Methods 100
4.10 Properties of methyl ester 103
4.10.1 Chemical Properties of Methyl Ester 103
4.10.2 Physical Properties of Methyl Ester 106
4.11 Combustion and Emission Analysis 107
4.11.1 Combustion Analysis 107
4.11.2 Emission Analysis 108
CHAPTER 5 CONCLUSION AND RECOMMENDATIONS 111
5.1 Conclusion 111
5.2 Recommendation 112
REFERENCES 113
PUBLICATIONS 127
xii
LIST OF TABLES
Table No. Title Page
2.1 Predicted annual increases in biodiesel production
(Mt)
11
2.2 Edible, non-edible and waste potential feedstock for
biodiesel process in worldwide
12
2.3 Different methods of biodiesel production 17
2.4 Fatty acids distribution of animal fats, greases and
vegetable oils
21
1
2.5 Comparison of reaction conditions and performance of
various types of feedstock from waste sources in the
production of biodiesel
22
2.6 Average international price of virgin vegetable oils,
waste grease and fat in 2007
27
2.7 Transesterification reaction catalyzed by homogeneous
catalysts
31
2.8 Transesterification reaction catalyzed by
heterogeneous catalysts
33
2.9 Summary of various types of waste catalysts in
transesterification
34
3.1 Refinability of CPO according DOBI values 47
4.1 Quality parameters of oils 60
4.2 Characterization of WPCO from different sources 60
4.3 Fatty acid composition of RBD-PO, WPCO and
chicken fat
61
xiii
4.4 Fatty acid composition of O-DC compared to crude
palm oil previous work
62
4.5 Decanter cake composition using EDX analysis 63
4.6 DOBI analysis of O-DC with different solvents
extracted
65
4.7 Surface area, pore volume and diameter of waste
catalysts dried and calcined
72
4.8 XRF results of waste catalysts from different sources 78
4.9 Basicity of catalyst in different temperature towards
Hammett indicators
79
4.10 Catalytic performances of waste catalysts 87
4.11 Methyl ester produced using CaO mixed-waste
catalyst
87
4.12 Methyl ester content of different feedstock using GC
and 1H-NMR using BA-500 as a catalyst
105
4.13 Properties of the prepared biodiesel with different
catalysts
107
xiv
LIST OF FIGURES
Figure No. Title Page
1.1 General cost breakdown for production of biodiesel 3
2.1 Comparison of net CO2 life cycle emissions for
petroleum diesel and biodiesel blends
10
2.2 Biodiesel production in EU 13
2.3 US biodiesel production 15
2.4 Chemical reaction for transesterification process 18
2.5 Possible mechanism of transesterification of WPCO
catalyzed by homogeneous base catalyst
30
2.6 Possible mechanism of transesterification of WPCO
catalyzed by CaO
32
2.7 Saponification reaction of fatty acid 41
2.8 Hydrolysis reaction of ester 41
2.9 Presence of water in transesterification reaction using
CaO catalyst
43
3.1 Boiler ash 48
3.2 Baby clam (Paphia undulata) shell 48
3.3 Capiz (Placuna placenta) shell 49
3.4 Transesterification reaction 51
3.5 TLC plate showing of methyl ester and mixture
standard C17 and oil in 1 h, using BA as a catalyst and
RBD-PO as a feedstock
52
4.1 Cumulative oil yield with different solvents 64
4.2 TGA thermogram of (A) BA, (B) BC-CaO and (C) C-
CaO
66
4.3 Decomposition of calcium carbonate 67
xv
4.4 Powder XRD patterns of (A) BA, (B) BC-CaO, (C) C-
CaO at various calcination temperatures ▲, K2MgSiO4
□, KAlO2 ♦, K9.6Ca1.2Si12O30 ◊, K4CaSi3O9 ■, CaO; ●,
CaCO3
69
4.5 BET adsorption-desorption isotherm of BA (A)
uncalcined and (B) calcined at 500 °C, 5 h
73
4.6 BET adsorption-desorption isotherm of BC (A)
uncalcined and (B) calcined at 900 °C, 2 h
73
4.7 BET adsorption-desorption isotherm of C (A)
uncalcined and (B) calcined at 900 °C, 2 h
73
4.8 FTIR spectra of (A) BA, (B) BC-CaO and (C) C-CaO
at various calcination temperature
75
4.9 SEM image of BA (A) dried, and calcined at (B)500
˚C, (C) 900 ˚C, 5 h
77
4.10 SEM image of BC-CaO (A) dried, and calcined at (B)
700 ˚C, (C) 900 ˚C, for 2 h
77
4.11 SEM image of C-CaO (A) dried, and calcined at (B)
700 ˚C, (C) 900 ˚C, for 2 h
77
4.12 The effect of calcination temperature on methyl ester
content
80
4.13 Influence of catalyst amount on methyl ester content
using (A) BA-500 (MeOH:oil molar ratio 12:1 for 1
h), (B) BC-CaO-900 and (C) C-CaO-900 (MeOH:oil
molar ratio 12:1 for 3 h)
82
4.14 Influence of MeOH:oil molar ratio on methyl ester
content using (A) BA-500 (3 wt.% catalyst for 1 h),
(B) BC-CaO-900 and (C) C-CaO-900 (5 wt.% catalyst
for 3 h)
84
4.15 Influence of reaction time on methyl ester content
using (A) BA-500(MeOH:oil molar ratio 9:1 for 1 h),
(B) BC-CaO-900 and (C) C-CaO-900 (MeOH:oil
molar ratio 12:1 for 3 h)
85
4.16 FTIR analysis of (A) spent of BA and (B) spent of BC-
C-Mixed catalyst before and after washing use
methanol and hexane
88
4.17 Methyl ester content from reused BA-500 89
xvi
4.18 Powder XRD patterns of (A) Spent BA and (B)
Regenerated BA ▲, K2MgSiO4 □, KAlO2 ♦,
K9.6Ca1.2Si12O30 ◊, K4CaSi3O9
90
4.19 Methyl ester content from reused BC-C-Mixed-900 91
4.20 Powder XRD patterns of (A) Spent BC-C-mixed and
(B) Regenerated BC-C-mixed
92
4.21 Transformation of calcium oxide to calcium
diglyceroxide with presence of glycerol
93
4.22 Methyl ester content using different catalyst amount
with various FFA content (A) BA-500 and (B) BC-C-
mixed-900
94
4.23 Methyl ester content using different MeOH:oil molar
ratio with various FFA content (A) BA-500 and (B)
BC-C-mixed-900
96
4.24 Saponification reaction of oleic acid 97
4.25 Methyl ester content using different catalyst amount
with various water content (A) BA-500 and (B) BC-C-
mixed-900
98
4.26 Methyl ester content using different MeOH/oil molar
ratio with various water content (A) BA-500 and (B)
BC-C-mixed-900
99
4.27 Effect of (A) catalyst amount; (B) methanol to oil
molar ratio; and (C) co- solvents ratio on methyl ester
content (reaction conditions: temperature 65 ˚C;
reaction time, 1 h)
101
4.28 Gas chromatogram methyl ester with BA-500 as a
catalyst
104
4.29 1H-NMR spectrum methyl ester with BA-500 as a
catalyst
105
4.30 Peak in-cylinder pressure curve with engine load, 5.5
MPa at 1200 rpm
108
4.31 The NOx emission of various engine speeds for
different test fuels
109
4.32 The CO emission of various engine speeds for
different test fuels
109
xvii
4.33 The CO2 emission of various engine speeds for
different test fuels
110
xviii
LIST OF ABBREVIATIONS
BA
BA-500
BC-CaO
BC-CaO-900
BC-C-Mixed-900
BET
CPO
DC
DOBI
EFB
FAME
FFA
FFB
GC-FID
GC-MS
GHG
1H-NMR
ICP-MS
ME
MeOH
O-DC
PE
RBD-PO
SBC
SEM
TGA/DTA
TLC
WPCO
XRD
XRF
Boiler ash
Boiler ash calcined at 500 ˚C, 5h
Baby clam shell calcium oxide
Baby clam shell calcium oxide calcined at 900 ˚C, 2h
Baby clam and capiz shell mixed calcined at 900 ˚C, 2h
Brunauer-Emmett-Teller
Crude palm oil
Decanter cake
Deterioration of bleachability index
Empty fruit bunch
Fatty acid methyl esters
Free fatty acids
Fresh fruit bunches
Gas chromatography-flame ionization detector
Gas chromatography–mass spectrometry
Greenhouse gases
Proton nuclear magnetic resonance
Inductively coupled plasma mass spectrometry
Methyl esters
Methanol
Oil extracted from decanter cake
Petroleum ether
Refined, bleached and deodourized palm olein
Spent bleaching clay
Scanning electron microscopy
Thermogravimetry analysis/ differential thermal analysis
Thin layer chromatography
Waste palm cooking oil
X-ray diffraction
X-ray fluorescence
1
CHAPTER 1
INTRODUCTION
1.1 INTRODUCTION
The global population is estimated to increase up to 30% in the next 25 years,
where 80-90% of the increase is predictable to be in developing countries (IEA, 2004).
At the same time, global energy demand is increasing in worldwide. United State,
Russia and China are the world‘s largest producers and consumers of world energy. In
the World Energy Outlook 2004, it is estimated that huge investments in production
capacity and infrastructure are needed in many countries to secure the necessary access
to energy (IEA, 2004). For many decades, fossil fuel is the most important energy
source, worldwide while the issues of pollution and fossil fuel reserve are high in
current decades. The global warming due to carbon dioxide emission will have a great
impact on the climate and the temperature of our earth where the increase is estimated
between 2 to 6 ˚C year 2100.
The growing awareness concerning the environmental issues on energy supply
and usage have recently been the topic of interest in research. Among various
alternative energy discovered, biodiesel is one of the promising blended fuel to
substitute petroleum derived diesel which offers friendly and sustainable environment.
Commonly, biodiesel is produced from neat vegetable oil such as soybean, palm,
rapeseed, and sunflower. The European Union (EU) uses rapeseed as a major biodiesel
lipid feedstock; the United State (US) utilizes oil from soybean for this purpose.
Biodiesel also called as fatty acid methyl ester (FAME) is derived from
vegetables oil or animal fats. Transesterification process is one of the methods to
2
produce biodiesel. In light of the fact that it is non-harmful, biodegradable and non-
combustible, biodiesel worldwide prevalence act as an elective vigour energy source.
Biodiesel has alternate gain in term of ecological profits. Biodiesel has shown
development environmental adaptation in comparison to conventional mineral diesel on
its usage. Biodiesel does not contain sulphur or aromatics and can be used in
conventional diesel engine which results in substantial reduction of carbon monoxide,
particulate matter and unburned hydrocarbons. The use and production of biodiesel
resulted in a 78.5% decrease in carbon dioxide emissions as reported by U.S
Department of Energy (EIA, 2014). If biodiesel is widely used, it could decrease the
carbon dioxide emissions in certain sector like in industry and transportation. There are
number of research about the comparison of petroleum diesel with biodiesel in term of
the performance of vehicle and the potential to reduce the emission of carbon. Biodiesel
absolutely can decrease the emissions of carbon and increase the security of energy
(Sheehan et al., 1998). With those reasons, we can prove that biodiesel has benefit in
term of cleaner environment.
Other than that, to improve the economy of biodiesel production and its
commercial production at the industry scale, the use of cheap feedstock is one of the
ways. To ensure low biodiesel production cost, the best feedstock need to be selected.
Feedstock alone accounted for 75% of the overall biodiesel production cost as shown in
Figure 1.1. Feedstock should be available at low price in order for biodiesel to remain
competitive compare to petroleum diesel. Others properties of feedstock includes low
agriculture inputs, favourable fatty acid composition, increase oil content and potential
market for agricultural by-products.
3
Figure 1.1: General cost breakdown for production of biodiesel
Source : Lim and Teong (2009)
In addition, the trend also indicates the need for large amounts of vegetable oil
supply and if the major portion of the oil comes from neat edible oil then the question of
food starvation arises. The concern in respect of food starvation or food for fuel already
constitutes a heated argument. With the increasing need for oil in the near future, it will
definitely complicate the situation, as globally there are 925 million people
undernourished; reported by the Food and Agriculture Organization of the United
Nations in 2011. Hence, the exploitation of raw materials waste source has been of
recent interest. Researchers have effectively utilized waste cooking oil (WCO), chicken
fat, beef tallow, spent bleaching clay (SBC), palm fatty acid distillate (PFAD), as a
source of feedstock biodiesel (Ma et al., 1999; Chin et al., 2009; Lim et al., 2009;
Malvade and Satpute, 2013, and Shi et al., 2013) .
In Malaysia, the biodiesel initiatives started in 2006, 12 biodiesel plants are in
operation, with a total annual production capacity of 1.22 million tonnes from January
to September in 2013 (Adnan, 2013). In June 2011, B5 biodiesel can be found in the
market, the B5 biodiesel is an addition of 5% biodiesel and 95% of regular petroleum-
based diesel which is suitable for the normal diesel engine vehicle without any
modifications. According to The Star Online, 2014, the biofuel option is often seen as a
safety net project for the palm oil sector, especially when the price of crude palm oil
(CPO) is about to hit rock bottom and the palm oil stockpile sits above the critical two
4
million tonne mark. If the price of CPO falls especially below RM800 per tonne, it is
best to go for biofuel or biodiesel and if the CPO price recovers, it will be switched
back to food related production. Therefore, given the current dire situation whereby
palm oil stocks are at a record high of 2.63 million tonnes and CPO price trading below
RM2,500 per tonne, the Government has once again decided to revisit the biofuel option
with focus on production and marketing of B10 biodiesel programme (Rittgers and
Wahab, 2013).
The utilization of waste/used edible oils as raw material is a relevant idea, and
there are many advantages for using waste feedstock for biodiesel production, namely
(i) abundant supply, (ii) relatively inexpensive, and (iii) environmental benefits
(Tashtoush et al., 2004; Boey et al., 2011c, and Wang et al., 2011). Waste oil in many
countries is in abundance. It was reported that, annually, EU recorded 0.7–1.0 million
tonnes of waste oil, Turkey 350,000 tonnes and Canada 120,000 tonnes, in addition to
those uncollected oils, which goes to waste through sinks and garbage and eventually
seeps into the soil and water sources (Balkanlioğlu, 2012). Furthermore, it is generally
accepted that reusing used cooking oil for human consumption is harmful to health (See
et al., 2006).
In addition, another waste oil source from decanter cake (DC) could be explored
to be a feedstock for biodiesel production. DC is a solid waste produced when the crude
palm oil is centrifuged for purification where the supernatant is the purer palm oil and
the sediment is the decanter cake. DC contains water (about 76%, on wet basis),
residual oil (about 12%, on dry basis) and nutrients, cellulose, lignin and ash. There are
previous reports on the use of DC in the area of bio-fertilizer, biofuel and cellulose
(Kandiah, 2012, and Razak et al., 2012). Oil adsorbed on DC is a minor by-product of
palm oil purification process with appreciable magnitude that could be a potential
feedstock for production of biodiesel (methyl ester).
A large range of industrial wastes, both natural and synthetic, are disposed
without extracting the useful components from them. Biomass is a promising source of
renewable energy that contributes to energy needs and is the best alternative for
guaranteeing energy for the future. Malaysia is the world‘s second largest producer of
5
palm oil and contributes 39% of the world‘s total palm oil production (GGS, 2013). The
total crude palm oil (CPO) produced was 19.22 million metric tonnes in 2013, with of
total 5.04 million hectares of land with oil palm trees (GGS, 2013, and MPOB, 2014),
has an estimated total amount of processed fresh fruit bunches (FFB) of 7.8 tonnes/ha,
70% of which is removed as waste, such as palm press fiber (30%), empty fruit bunches
(EFB, 28.5%), palm kernel shell (6%), decanter cake (DC, 3%) and others (2.5%)
(Ramli et al., 2012, and Zafar, 2013). As such, in the processing of 39 million tonnes of
FFB annually (7.8 tonnes/ha x 5 million ha), 1.17 million tonnes of waste DC (3% of 39
million tonnes FFB) is generated in Malaysia alone. Indeed, the boiler ash (BA) used as
a catalyst in this work is also a waste by-product of palm oil mill. Generally, in palm oil
mill, approximately 5% of BA is produced upon the burning of dry EFB, fiber and shell
in boiler (Tangchirapat et al., 2007; Boey et al., 2011a, and 2012).
Currently, BA which is the by-products of oil processing is only used as boiler
fuel and combustion ash is used as a substitute for fertilizer (Salètes et al., 2004) or
animal feed (Zahari et al., 2012). Palm empty fruit bunches combustion ash has high
potassium levels (45-50%) (Onyegbado et al., 2002). Some literature has reported the
utilization of BA as a base catalyst in the synthesis of biodiesel. Researchers previously
reported the BA utilization as a source of K2CO3 catalysts for the synthesis of biodiesel
from coconut oil (Imaduddin et al., 2008). Other researchers also reported the influence
of ash of palm EFB in palm oil transesterification to biodiesel (Yoeswono et al., 2007).
Transesterification is usually carried out using homogeneous catalyst (sodium or
potassium hydroxide). However, the process has few drawbacks, in this situation the use
of heterogeneous catalyst is a better solution. Therefore, a new process using
heterogeneous catalyst has been developed for environment-friendly and reduction of
production cost. There are many types of heterogeneous catalysts from waste, such as
waste egg, crab, and oyster shells; bone and ash (Boey et al., 2009a; Nakatani et al.,
2009; Chakraborty et al., 2010; Boey et al., 2011b, and Obadiah et al., 2012). Baby
clam (Paphia undulata) is a species of saltwater clam, this species inhabits inshore
shallow sandy seabed in Southeast Asia. Paphia undulata is second most important
bivalve in Malaysia in term of total production. Estimated potential annual production is
20,000 metric tonnes (Sin and Mahmood, 2013). On the other hand, capiz (Placuna
6
placenta) is a successful source with abundant and diverse populations.
Placuna placenta is a highly asymmetrical bivalve with a characteristically thin,
translucent shell often used in handicrafts such as lampshades. It lives mostly on
mangrove coasts from the Arabian sea to the coast of China. Populations are
concentrated in the Gulf of Aden [12°N, 48°E], the coast of India [21°N, 78°E], the
Malaysia Peninsular [3°N, 101°E], the southern coasts of China [19°N, 109°E], and the
northern coasts of Borneo [4°N, 114°E] to the Philippines [14°N, 121°E]. The major
compound of capiz is calcium carbonate (Suryaputra et al., 2013), therefore baby clam
and capiz could be potential sources of CaO since they consist of >90 % of CaCO3 and
upon heat treatment the CaCO3 could be easily converted to CaO.
The utilization of oil and catalyst from waste sources could also counter the
environmental damage. Furthermore, within the last 5 years, many research works have
focused on the exploitation of waste materials as catalysts for the production of
biodiesel. They include shells, ashes, rock, and bone (Xie et al., 2009; Boey et al.,
2011d; Ilgen, 2011, and Obadiah et al., 2012). Due to their abundance and low cost, the
exploitation of such waste materials has become very attractive. As such, this work
focusing on feedstock and catalysts from waste sources in the preparation of methyl
esters.
1.2 PROBLEM STATEMENT
There are some problems that need to be encounter in order to produce biodiesel
and one of the main problem is the major cost for the biodiesel production which mainly
due to the cost of feedstock. Using a low cost oil for biodiesel production become very
attractive, in this work the feedstock been sourced from waste oil is waste palm cooking
oil (WPCO) as well as palm olein, while oil extracted from decanter cake also was
investigated as a new waste source. On the other hand, waste oil is low in quality
feedstock as such need a suitable catalyst to tolerance the moisture and FFA. Typically,
production of biodiesel by transesterification using typical catalyst including NaOH,
KOH or their alkoxides. This work involved the production of biodiesel also utilization
waste sources as a catalyst, the catalyst derived from waste sources such as from ash
and shells which is cost effective with good availability. Other than that, solid catalyst
7
which has the capability to tolerate the moisture and fatty acid in the feedstock and it
also can be recycled. By utilizing the waste matters, the cost of the production biodiesel
could be decreased, and natural mineral resources could be utilized as well.
1.3 OBJECTIVES
The objectives of this study are:
i. To utilize catalysts produced from boiler ash, baby clam shell and capiz shell in
transesterification of refined, bleached and deodorized palm olein (RBD-PO)
and waste palm cooking oil (WPCO).
ii. To study the reusability of the catalysts and their tolerance towards moisture and
FFA in waste palm cooking oil.
iii. To compare methyl ester conversion between single step (in situ) method using
ultrasound irradiation and mechanical stirring methods using decanter cake (DC)
as a feedstock.
1.4 SCOPE OF STUDY
Based on the objectives, the major scope of this experiment is to find out the
effectiveness of catalyst from waste sources to transesterify the low cost feedstocks. In
this experiment the boiler ash, baby clam shell and capiz shell as a waste catalysts were
utilized to transesterify refined, bleached and deodorized palm olein (RBD-PO) and
waste palm cooking oil (WPCO). The reusability and capability of the catalysts from
the boiler ash and mixed shell (baby clam and capiz) toward moisture and FFA that are
present in the WPCO were also investigated. In situ transesterification of decanter cake
(DC), as a new feedstock, by ultrasound and mechanical stirring using boiler ash as a
catalyst was studied. In addition, the engine performance of WPCO B10 was compared
to petro-diesel fuel using diesel engine (YANMAR NF19-SK) was investigated.
8
CHAPTER 2
LITERATURE REVIEW
2.1 BIODIESEL
Increasing concerns on the potential of global climate change, declining air and
water quality, and human health are inspiring the development of biodiesel, as a
renewable, cleaner burning diesel alternative. The alternatives to diesel fuel must be
technically feasible, economically competitive, environmental acceptable and readily
available (Mahanta and Shrivastava, 2008). Many of these requisites are satisfied by
vegetable oil or in general by triglyceride. Indeed, vegetable oils are widely available
from a variety of sources and they are renewable (Encinar et al., 2007).
Biodiesel fuel based on vegetable oil, such as methyl or ethyl ester, have the
following advantages over diesel fuel: high cetane number, produce lower carbon
monoxide and hydrocarbon emissions, are biodegradable and non-toxic, provide engine
lubricity to low sulfur diesel fuels and and so is environmentally beneficial (Ma and
Hanna, 1999; Demirbas, 2003, and 2005). Biodiesel contains electronegative elemental
oxygen, therefore it is slightly more polar than diesel fuel, and as a result the viscosity
of biodiesel is higher than that of diesel fuel. The heating value of biodiesel is lower
than diesel fuel due to the presence of elemental oxygen (Deshpande and Kulkarni,
2012).
The high cost of biodiesel production, which is 1.5 to 3 times higher than that of
petroleum diesel, is an obstacle in the use of biodiesel (Zhang et al., 2003; Haas et al.,
2006, and Liu et al., 2012). Biodiesel can be blended with diesel to reduce the
particulate emissions from the engine as well as the cost impact of biodiesel. Biodiesel
9
can be either used in its pure form (B100) or can be blended with mechanical stirring
diesel (e.g. B5, B10 and B20). Biodiesel can also be used as an additive because it is a
very effective lubricity enhancer (Ball et al., 1999). Biodiesel also exhibits potential for
compression-ignition engines without the need for engine modification (Wang et al.,
2000, and Kumar et al., 2010).
Biodiesel also can reduces the life-cycle greenhouse gas (GHG) emissions by
displaces the petroleum. The GHG emissions benefits of biodiesel are especially
significant, because carbon dioxide (CO2) released during fuel combustion is offset by
the CO2 captured by the plants from which biodiesel is produced. The CO2 in the air
absorbed by the plant when it grows. In addition, when the biodiesel can be obtained
from the oil extracted from plant as soybeans, when it burned, the CO2 and other
emissions are released and returns to the atmosphere. The CO2 concentration in the
atmosphere does not increase because the CO2 will be reuse by plant when it grows.
Sheehan et al. (1998) studied the total life cycles of CO2 released at the tailpipe
biodiesel and petroleum diesel based on the combustion of fuel in the bus. As shown in
Figure 2.1, the overall life cycle emissions of CO2 from B100 are 78.45% lower than
those of petroleum diesel. B20, the most commonly used form of biodiesel in the US,
reduces net CO2 emissions by 15.66% per gallon of fuel used.
10
Figure 2.1: Comparison of net CO2 life cycle emissions for petroleum diesel and
biodiesel blends
Source: Sheehan et al. (1998)
2.2 HISTORICAL BACKGROUND ON BIODIESEL PRODUCTION
Transesterification of triglycerides in oils is not a new process.
Transesterification of vegetable oil was conducted as early as 1853, by scientists E.
Duffy and J. Patrick, many years before the first diesel engine became functional. Life
for the diesel engine begin on August 10, 1893 in Augsburg, Germany when famous
German inventor Dr. Rudolf Diesel published a paper entitled ―The theory and
construction of a rational heat engine‖. He demonstrated his compression ignition
engine by using peanut oil the first biodiesel as a prototype engine on his prime model,
a single 10 ft (3 m) iron cylinder with a flywheel at its base. August 10th
has been
declared International Biodiesel Day. In 1900 Diesel again demonstrated his engine at
the World Fair in Paris, France and received the Grand Prix (highest prize). In 1912
speech, Rudolf Diesel said ―The use of vegetable oils for engine fuels may seem
insignificant today, but such oils may become, in the course of time, as important as
petroleum and the coal tar products of the present time‖ (Haas and Foglia, 2005).
0
100
200
300
400
500
600
700
Petroleum diesel B20 B100
g C
O2/b
hp-h
Net CO2